Grinding & Classification Circuits

Grinding & Classification Circuits2018-06-17T09:51:34-05:00
  • To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Grinding.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

Geared and gearless Drives of Tumbling Mills (No replies)

3 weeks ago
Dachmann 3 weeks ago


I was told in this forum that economic efficiency is one of the major reasons for the ongoing popularity of Tumbling Mills in mineral processing. Concerning my questions I need some insight of experts with practical experience.

Looking at SAG mills for instance there are huge differences in CAPEX regarding their different drive systems. Especially in the the multi-MW class gearless drive systems seem to be a thing because of their advantages such as variable speed control and low maintenance requirements. How much of the total costs of a SAG mill relate to the drive system?

I wonder why geared drive systems are popular in the lower MW class but lose on relevance with increasing power, even though there are geared solutions rated up to 32MW (Metso QdX4). What are the practical reasons behind this? I mean, at least some lower developed countries could have invested in a geared system to save a decent amount of money. 

I assume that maintenance is a major factor since the large ring gear is exposed to dirt and high forces. Why then, did'nt other gear designs come into favor such as seen here:

Please give me detailed info as why you think this is not a practical solution.


Thank you very much for your insight.




Please join and login to participate and leave a comment.

BUY Laboratory & Small Plant Process Equipment

We have all the laboratory and plant equipment you need to test or build/operate your plant.

ENTER our Mining Equipment' Store

We Sell EQUIPMENT for all types of Mineral Treatment PROCESSES and Laboratory Testing needs


View the Services we Provide

911Metallurgist Mineral Processing & Process Development Laboratory

We have a metallurgical test for every possible mineral type and treatment.


We can IMPROVE ALL PLANTS / Mineral Processing Engineering & LABORATORY Ore Testing

911Metallurgy Engineering

Contact us for process engineering, metallurgical investigations, plant optimization, plant troubleshooting, needs. WE “FIX” METALLURGY.

I Need Consulting Engineering Help
I Need Ore Laboratory Testing